FullyImperative.java

// Example of a fully imperative approach to writing Java code...
public class FullyImperative {
 
    // @Inject
    private final ItemRepository itemRepository;
    // @Inject
    private final InventoryLocationRepostitory inventoryLocationRepostitory;

    // Find the first available InventoryLocation for a given item id. 
    public InventoryLocation itemByFirstAvailable(String itemId)
            throws NotFoundException {

        // Null check 
        if(null == itemId) {
            throw new InvalidParameterException("itemId cannot be null");
        }

        // Retrieve the item
        Item item = itemRepository.findByItemId(itemId);

        // Throw an exception if the item doesn't exist
        if(null == item) {
            throw new NotFoundException("Item " + itemId + " not found");
        }
    
        // Get a List of all of the inventory locations for this item
        List<InventoryLocation> inventoryLocations = inventoryLocationRepostitory.findByItemId(item);

        // If we couldn't find any return null
        if(null == inventoryLocations || inventoryLocations.isEmpty()) {
            return null;
        }
    
        // Default inventory location is none
        InventoryLocation inStockLocation = null;

        // Loop through locations for this item
        for(InventoryLocation location : inventoryLocations) {
            // Finally some business logic! Return the first in stock location
            if(location.getInStock() > 0) {
                inStockLocation = location;
                break;
            }
        }
        return inStockLocation;
    }
} 
  
}